For the purpose of preserving grain for a long time by preventing spoilage of grain and occurrence of harmful insects, grain containers need to be maintained at a low temperature. Up to now, a variety of grain refrigerators have been researched and developed. Specifically, rice must be preserved at a low temperature in order for a long preservation and a protection from insects. By doing so, the flavor of rice also becomes good. For this reason, rice only refrigerators have been developed.
In conventional grain refrigerators, an evaporator is installed in a wall. Therefore, among a grain receiving space, an area adjacent to the wall is at the lowest temperature and a central area apart from the wall is at relatively high temperature. Like general refrigerators, since air convection phenomenon inside a storage space is limited due to grain, it is very difficult to maintain an overall storage space to uniform temperature. In case of large-sized grain refrigerators used in place of business, such as a restaurant, the difficulty becomes greater.
Additionally, in case of lowering the temperature for maintaining a central area of the grain refrigerator at a low temperature, dew condensation occurs at an area adjacent to the wall causing grain to be damaged.
Recently, because people want to drink water of appropriate temperature, water purifiers and water cooler/heaters become the necessary household electric appliances. Additionally, in order to reduce an installation space, a combination equipment integrally constructed with both the grain refrigerator and the water cooler/heater tends to be developed.
According to the grain refrigerators having a conventional water cooler/heater, however, a rice chest and a water cooler/heater are operated individually according to a refrigeration cycle having two kinds of refrigerant flows. Therefore, the number of parts increases and a manufacturing cost rises due to a complex installation structure. Further, the conventional grain refrigerators have a problem in that malfunctions may occur frequently.